A dental instrument of this type is already known from Italian Patent Application No. RC94U 000011, which has the same inventor as the present application. This instrument comprises:
a casing having a shape reproducing the shape of the dental arches and able to maintain the patient's mouth open once inserted into it in contact with the dental arches; and PA1 a saliva discharge opening communicating with a tube for removing the saliva by suction applied to the other end of the tube.
The aforedescribed instrument is conveniently provided with means for coupling the instrument to the patient's teeth in order to maintain the instrument in position relative to the patient's mouth.
Using such an instrument, it has been found that although being very useful in achieving sufficient opening of the patient's mouth, its casing is too bulky in the mastication direction, so that it is uncomfortable to insert into the patient's mouth.
Moreover, because of its size in mastication direction, the known dental instrument does not leave sufficient space free for the dentist to carry out the operations required within the patient's mouth with ease.